KR20220131330A - Corrective Polarization Compensation Optics for Display Systems - Google Patents

Abstract

This disclosure relates generally to techniques for improving the performance and efficiency of display systems, such as laser scan beam display systems or other types of display systems (eg, micro-displays). The display systems of the present disclosure provide polarization compensation to provide light well suited for polarization sensitive optics of display systems, such as waveguide-based optical systems, pancake optical systems, bird bath optical systems, coating-based optical systems, and the like. polarization compensating optics, such as spatially varying polarizers, that provide a phase retardation that varies as a function of position. The display systems of this disclosure may be components of head-worn display systems, or other types of display systems.

Description

Corrective Polarization Compensation Optics for Display Systems

BACKGROUND This disclosure relates generally to display systems, and more particularly, to improving the efficiency and performance of display systems.

One current creation of virtual reality (“VR”) experiences is tethered to a stationary computer (eg, a personal computer (“PC”), laptop, or game console), smart phone and/or its associated Created using head-mounted displays (“HMDs”), which may be combined with and/or integrated with a display, or may be self-contained. In general, HMDs are display devices worn on a user's head, with a small display device in front of one (monocular HMD) or each eye (binocular HMD). Display units are typically miniaturized and may include, for example, CRT, LCD, Liquid crystal on silicon (LCoS), OLED technologies, or laser scan beam displays. Binocular HMDs have the potential to display different images in each eye. This capability is used to display stereoscopic images.

The demand for displays with high performance has increased with the growth of smartphones and high-definition televisions as well as other electronic devices. The growing popularity of virtual and augmented reality systems, particularly virtual and augmented reality systems using such HMDs, is further increasing this demand. Virtual reality systems typically completely enclose the wearer's eyes and displace a "virtual" reality view of a real or physical reality in front of the wearer, whereas augmented reality systems typically envelop the wearer so that the real view is augmented with additional information. providing a semi-transparent or transparent overlay of one or more screens in front of the eyes of the , mediated reality systems similarly present information combining real elements with virtual elements to the viewer. can

The display system includes: a display light source; and a pupil relay system positioned to relay the first pupil from the display light source to a second pupil in the viewer's eye, the pupil relay system comprising: a polarization sensitive optic; and a spatially varying polarizer having a spatially varying polarization as a function of position to provide polarization compensation for the polarization sensitive optics.

The spatially varying polarizer may include a multi-twist retarder. A spatially varying polarizer may provide no delay in a first position and may provide a quarter wave delay in a second position. The spatially varying retardation of the polarizer can vary as a function of either a horizontal dimension or a vertical dimension. The spatially varying delay of the polarizer may vary over the field of view of the display system. The polarization-sensitive optics may include a waveguide-based optical system, a pancake optical system, a birdbath optical system, or a coating-based optical system. The display light source may include a laser light source, and the display system may further include a scan mirror positioned to receive the light beam from the laser light source and relay the received light toward the pupil relay system.

The display system may further include beam forming optics positioned between the laser light source and the scan mirror.

At least a portion of the spatially varying polarizer may be positioned on, adjacent to, or within the polarization-sensitive optic. The polarization-sensitive optics may include a waveguide, and the spatially varying polarizer may be positioned on, within the waveguide, or proximate a port of the waveguide. The display system may be a display system of a head-worn display system.

The display system may further include control circuitry operatively coupled to the spatially varying polarizer, the control circuitry operative to selectively adjust a delay provided by the spatially varying polarizer.

The display source may include a micro-display, and the spatially varying polarizer may be positioned adjacent the micro-display. A spatially varying polarizer may be attached to the micro-display. A spatially varying polarizer may provide telecentricity to the light emitted by the micro-display. The spatially varying polarizer may include a surface phase map that provides polarization compensation for at least one of the display source and the polarization sensitive optics.

A head-worn display system comprising: a support structure; and a display system coupled to the support structure, the display system comprising:

display light source; and a pupil relay system positioned to relay the first pupil from the display light source to a second pupil in the viewer's eye, the pupil relay system comprising: polarization sensitive optics; and a spatially varying polarizer having a spatially varying polarization as a function of position to provide polarization compensation for the polarization sensitive optics.

The spatially varying polarizer may include a multi-twist retarder. The spatially varying retardation of the polarizer may vary as a function of the horizontal dimension, the vertical dimension, or the field of view of the display system. The polarization-sensitive optics may include a waveguide-based optical system, a pancake optical system, a birdbath optical system, or a coating-based optical system.

A head-worn display system comprising: a support structure; and a display system coupled to the support structure, the display system comprising:

laser light source; a scan mirror positioned to receive the light beam from the laser light source; and a pupil relay system positioned to relay the first pupil received from the scan mirror to a second pupil in the viewer's eye, the pupil relay system comprising: polarization sensitive optics; and a spatially varying polarizer having a spatially varying polarization as a function of position to provide polarization compensation for the polarization sensitive optics.

The spatially varying polarizer may include a multi-twist retarder. The spatially varying retardation of the polarizer may vary as a function of the horizontal dimension, the vertical dimension, or the field of view of the display system. The polarization-sensitive optics may include a waveguide-based optical system, a pancake optical system, a birdbath optical system, or a coating-based optical system.

In the drawings, like reference numbers identify like elements or acts. The sizes and relative positions of elements within the figures are not necessarily to scale. For example, the shapes and angles of the various elements are not necessarily to scale, and some of these elements may be arbitrarily expanded and positioned to improve drawing readability. Additionally, the particular shapes of the illustrated elements are not necessarily intended to convey any information regarding the precise shape of the particular elements, but may be chosen merely for ease of recognition within the drawings.
1 is a schematic diagram of a networked environment including one or more systems suitable for performing at least some techniques described in this disclosure.
FIG. 2 is a diagram illustrating an example environment in which at least some of the described techniques are used with an example head-worn display display that is tethered to a video rendering system and provides a virtual reality display to a user.
3 is a schematic front view of an exemplary HMD device having binocular display subsystems.
4 illustrates a top plan view of an HMD device with binocular display subsystems and various sensors, in accordance with an exemplary embodiment of the present disclosure.
5 is a schematic block diagram of a display system including a spatially varying polarizer, according to one non-limiting illustrated implementation.
6 is a schematic diagram of a scan beam display system, according to one non-limiting illustrated implementation.
7 is a schematic diagram of a scan beam display system including a spatially varying polarizer, according to one non-limiting illustrated implementation.
8 is a schematic diagram of a display system including a waveguide-based optical system and a spatially varying polarizer, according to one non-limiting illustrated implementation.
9 is an HMD device comprising compensation optics positioned adjacent a display panel that provides at least one of polarization correction and telecentricity, according to one non-limiting illustrated implementation. is a schematic diagram of
FIG. 10 is an exemplary surface phase map of the compensating optic of FIG. 9 , according to one non-limiting illustrated implementation.
11 is another example surface phase map for the compensating optics of FIG. 9 , according to one non-limiting illustrated implementation.

In the following description, certain specific details are set forth in order to provide a thorough understanding of the various implementations disclosed. However, one of ordinary skill in the art will recognize that embodiments may be practiced without one or more of these specific details or in conjunction with other methods, components, materials, etc. In other instances, well-known structures associated with computer systems, server computers, and/or communication networks have not been shown or described in detail in order to avoid unnecessarily obscuring the description of the implementations.

Unless the context requires otherwise, throughout the following specification and claims, the word "consisting of" is synonymous with "comprising" and is inclusive and open-ended (ie, additional, unrecited elements or method acts). not excluded).

Recitation of such descriptions to “one embodiment” or “an embodiment” throughout this specification means that a particular feature, structure, or characteristic described in connection with the embodiment is included in at least one embodiment. Thus, the appearances of the phrases "in one embodiment" or "in one embodiment" in various places throughout this specification are not necessarily all referring to the same implementation. Additionally, the particular features, structures, or characteristics may be combined in any suitable manner in one or more implementations.

As used herein and in the appended claims, the singular forms "a", and "the" include plural referents unless the context clearly dictates otherwise. The term “or” is generally employed in its sense including “and/or” unless the context clearly dictates otherwise.

The headings and summary of the disclosure provided herein are for convenience only and do not interpret the meaning or scope of the embodiments.

This disclosure relates generally to techniques for improving the performance and efficiency of display systems, such as laser scan beam display systems or other types of display systems (eg, micro-displays). As discussed further below, at least some embodiments of the present disclosure provide polarization-sensitive optics of display systems, such as waveguide-based optical systems, pancake optical systems, birdbath optical systems, coating-based optical systems, and the like. Improves the performance of display systems by providing a spatially varying polarizer that provides a phase retardation that varies as a function of position, which produces light that is highly appropriate for the light and provides polarization compensation. These techniques significantly improve the intensity of light passing through the polarization sensitive optics while also reducing undesirable stray light.

First, an exemplary head-worn display device application for the techniques described herein is discussed with reference to FIGS. 1-4 . Referring then to FIGS. 5-8, exemplary implementations of display systems including polarization compensating optics are discussed.

Exemplary head-worn display systems and environments

1 depicts local media rendering, including a local computing system 120 and a display device 180 (eg, an HMD device having two display panels) suitable for performing at least some techniques described herein. A schematic diagram of a networked environment 100 including a local media rendering (LMR) system 110 (eg, a gaming system). In the depicted embodiment of FIG. 1 , local computing system 120 may be wired or tethered via (eg, one or more cables (cable 220 ) as illustrated in FIG. 2 ) or its It is communicatively coupled to the display device 180 via a transmit link 115 (which may instead be wireless). In other embodiments, local computing system 120 is configured for display on a panel display device (eg, TV, console, or monitor) via a wired or wireless link in addition to or instead of HMD device 180 . may provide encoded image data, each of the display devices including one or more addressable pixel arrays. In various embodiments, local computing system 120 may include a general purpose computing system; gaming console; video stream processing device; a mobile computing device (eg, a wireless telephone, PDA, or other mobile device); VR or AR processing device; or other computing systems.

In the illustrated embodiment, local computing system 120 includes one or more hardware processors (eg, central processing units, or “CPUs”) 125 , memory 130 , various I/O (“) input/output") hardware components 127 (eg, keyboard, mouse, one or more gaming controllers, speakers, microphone, IR transmitter and/or receiver, etc.), one or more specialized hardware processors (eg, Video subsystem 140 including, for example, graphics processing units, or “GPUs,” 144 and video memory (VRAM) 148 , computer-readable storage 150 , and a network connection ( 160). Further, in the illustrated embodiment, one embodiment of the eye tracking subsystem 135 may, for example, include the CPU(s) 125 and/or the CPU(s) 125 to perform automated operations implementing these described techniques. or by GPU(s) 144 to perform at least some of the techniques described, memory 130 optionally being displayed (eg, such as a game program). It may further execute one or more other programs 133 (for generating video or other images). As part of the automated operations for implementing at least some techniques described herein, the eye tracking subsystem 135 and/or programs 133 running within the memory 130 are examples of the storage 150 . Various types of data may be stored and/or retrieved, including within a database data structure, in which case the data used may include various types of image data information within a database (“DB”) 154 . , various types of applications in DB 152 , various types of configuration data in DB 157 , and may include additional information such as system data or other information.

In the illustrated embodiment, the LMR system 110 is also an exemplary network- capable of further providing content to the LMR system 110 for display, in addition to or instead of the image-generating programs 133 . It is communicatively coupled to an accessible media content provider 190 via one or more computer networks 101 and network links 102 . Media content provider 190 may have components similar to those of local computing system 120 , each including one or more hardware processors, I/O components, local storage devices, and memory. may include one or more computing systems (not shown), but some details are not illustrated for a network-accessible media content provider for the sake of brevity.

Although display device 180 is shown as separate and distinct from local computing system 120 in the illustrated embodiment of FIG. 1 , in certain embodiments, some or all components of local media rendering system 110 . It will be appreciated that the devices may be integrated or housed within a single device, such as a mobile gaming device, portable VR entertainment system, HMD device, and the like. In such embodiments, transmit link 115 may include, for example, one or more system buses and/or video bus architectures.

As an example involving operations performed locally by the local media rendering system 120 , the local computing system is a gaming computing system such that application data 152 uses memory 130 to load CPU 125 . including one or more gaming applications executed through it, and that various video frame display data is generated and/or processed by image-generating programs 133 , for example, in conjunction with GPU 144 of video subsystem 140 . assume that it will be A high volume of video frame data (corresponding to a high image resolution for each video frame as well as a high "frame rate" of about 60-180 of these video frames per second) is stored in the local computing system to provide a quality gaming experience. 120 and provided to the display device 180 via a wired or wireless transmission link 115 .

It will also be understood that computing system 120 and display device 180 are exemplary only and are not intended to limit the scope of the present disclosure. Computing system 120 may instead include multiple interactive computing systems or devices, via one or more networks such as the Internet, via the web, or private networks (eg, mobile communication networks). , etc.) may be connected to other devices not illustrated. Even more generally, a computing system or other computing node includes, but is not limited to, desktop or other computers, game systems, database servers, network storage devices and other network devices, PDAs, portable telephones, cordless telephones. Various other consumer devices, including pagers, electronic notebooks, Internet appliances, television-based systems (using, for example, set-top boxes and/or personal/digital video recorders), and suitable communication capabilities. Products may include any combination of hardware or software that can interact and perform the functions of the types described, including products. Display device 180 may similarly include one or more devices having one or more display panels of various types and forms, and may optionally include various other hardware and/or software components.

While various items are illustrated as being stored in memory or on storage while in use, it is also understood that such items or portions thereof may be transferred between memory and storage devices for purposes of memory management or data integrity. will be Accordingly, in some embodiments, some or all of the described techniques may be implemented by, for example, one or more software programs and/or by data structures (eg, execution of software instructions in one or more software programs). and/or by storage of such software instructions and/or data structures), may be performed by hardware including one or more processors or other configured hardware circuitry or memory or storage. Some or all of the components, systems, or data structures may also include a hard disk or flash drive or other non-volatile storage device, volatile or non-volatile memory (eg, , RAM), a network storage device, or a portable media article (eg, a DVD disk, a CD disk, an optical disk, etc.), on a non-transitory computer-readable storage medium (eg, software instructions or as structured data).

In some embodiments, systems, components, and data structures may also be generated as data signals (eg, as generated data signals on various computer-readable transmission media, including wireless-based and wired/cable-based media). It may be transmitted as part of a carrier wave or other analog or digital propagated signal) and may take various forms (e.g., as part of a single or multiplexed analog signal, or as multiple discrete digital packets or frames). . Such computer program products may also take other forms in other embodiments. Accordingly, the present invention may be practiced with other computer system configurations.

FIG. 2 illustrates a video rendering computing system in which at least some of the described techniques work over a tethered connection 220 (or a wireless connection in other embodiments) to provide a virtual reality display to a human user 206 . It illustrates an example environment 200 for use with an example HMD device 202 coupled to 204 . A user wears the HMD device 202 and receives information displayed through the HMD device from a computing system 204 in a simulated environment different from the real physical environment, wherein the computing system includes a game running on the computing system. It serves as an image rendering system that supplies images of the simulated environment, such as images generated by the program and/or other software programs, to the HMD device for display to a user. In this example, the user may further roam within the tracked volume 201 of the real physical environment 200, one or more I/O ( "input/output") devices, which in this example include hand-held controllers 208 and 210 .

In the illustrated example, environment 200 includes one or more base stations 214 (two shown and labeled) that may facilitate tracking of HMD device 202 or controllers 208 and 210 . base stations 214a and 214b). As the user moves the location or changes the orientation of the HMD device 202 , the location of the HMD device is tracked, eg, to enable a corresponding portion of the simulated environment to be displayed to the user on the HMD device. , controllers 208 and 210 may further utilize similar techniques for use in tracking the location of the controllers (and optionally using that information to assist in determining or verifying the location of the HMD device). can After the tracked location of the HMD device 202 is known, corresponding information is transmitted via the tether 220 or wirelessly to the computing system 204 , which generates one or more subsequent images of the simulated environment for display to the user. It uses the tracked location information to generate.

There are a number of different methods of tracking a location that can be used in various implementations of the present disclosure, including, but not limited to, acoustic tracking, inertial tracking, magnetic tracking, optical tracking, combinations thereof, and the like.

In at least some implementations, the HMD device 202 may include one or more optical receivers or sensors that may be used to implement the tracking function or other aspects of the present disclosure. For example, the base stations 214 may each sweep an optical signal across the tracked volume 201 . Depending on the requirements of each particular implementation, each base station 214 may generate more than one optical signal. For example, a single base station 214 is typically sufficient for 6-DOF tracking, while multiple base stations (eg, base stations 214a, 214b) are robust to HMD devices and peripherals. It may be necessary or desired in some embodiments to provide room-scale tracking. In this example, optical receivers are integrated into HMD device 202 and or other tracked objects, such as controllers 208 and 210 . In at least some implementations, optical receivers may be paired with an accelerometer and gyroscope Inertial Measurement Unit (“IMU”) on each tracked device to support low-latency sensor fusion.

In at least some implementations, each base station 214 includes two rotors that sweep a linear beam across the tracked volume 201 on orthogonal axes. At the beginning of each sweep cycle, the base station 214 may emit an omni-directional light pulse (referred to as a “sync signal”) visible to all sensors on the objects being tracked. Thus, each sensor calculates a unique angular position within the swept volume by timing the duration between the sync signal and the beam signal. Sensor distance and orientation can be addressed using multiple sensors attached to a single rigid body.

One or more sensors located on the tracked objects (eg, HMD device 202 , controllers 208 and 210 ) may include an optoelectronic device capable of detecting modulated light from the rotor. . For visible or near-infrared (NIR) light, silicon photodiodes and suitable amplifier/detector circuitry may be used. Because environment 200 can include static and time-varying signals (optical noise) having wavelengths similar to those of base station 214 signals, in at least some implementations, the base station light can transform it into any interfering signal. It can be modulated in a way to make it easy to distinguish from the other and/or in a way that filters the sensor from any wavelength of radiation other than the base station signals.

Inside-out tracking may also be used to track the location of HMD device 202 and/or other objects (eg, controllers 208 and 210 , tablet computers, smartphones). A type of location tracking that can be used. Inside-out tracking differs from outside-in tracking by the location of cameras or other sensors used to determine the location of the HMD. For inside-out tracking, the camera or sensors are located on the HMD or object being tracked, whereas in outside-out tracking the camera or sensors are located at a fixed location within the environment.

An HMD that uses inside-out tracking uses one or more cameras to “look out” to determine how its position changes with respect to the environment. As the HMD moves, the sensors readjust their position within the room, and the virtual environment responds accordingly in real time. This type of location tracking can be accomplished with or without markers located within the environment. Cameras positioned on the HMD observe features of the surrounding environment. When using markers, the markers are designed to be easily detected by the tracking system and positioned within a specific area. Using “markerless” inside-out tracking, the HMD system uses unique properties (eg, natural features) originally present in the environment to determine location and orientation. The HMD system's algorithm identifies specific images or shapes and uses them to calculate the device's position in space. Data from accelerometers and gyroscopes may also be used to increase the precision of position tracking.

3 shows information 300 that illustrates a front view of an example HMD device 344 when worn on the head of a user 342 . The HMD device 344 includes a front-facing or front-facing camera 346 and a front-facing structure 343 supporting a plurality of sensors 348a - 348d (collectively 348) of one or more types. . As an example, some or all of the sensors 348 may emit light to detect and use light information emitted from one or more external devices (not shown, eg, the base stations 214 of FIG. 2 ). As with sensors, it can help determine the location and orientation of device 344 in space. As shown, the front camera 346 and sensors 348 are directed forward towards the actual scene or environment (not shown) in which the user 342 operates the HMD device 344 . The actual physical environment may include, for example, one or more objects (eg, walls, ceilings, furniture, stairs, cars, trees, tracking markers, or any other type of objects). have. The specific number of sensors 348 may be fewer or more than the number of sensors shown. HMD device 344 (eg, using a combination of accelerometer and gyroscope, and, optionally, magnetometers) determines the specific force, angular rate, and/or HMD device of HMD device 344 . It may further include one or more additional components that are not attached to the redirecting structure (eg, inside the HMD device), such as an IMU (Inertial Measurement Unit) 347 electronic device that measures and reports the surrounding magnetic field. . The HMD device, as discussed in more detail below with respect to FIG. 4 , may include one or more attached attachments for changing the alignment or other positioning of one or more of the display panels and/or optical lens systems within the HMD device. Additional components not shown may further include one or more display panels and optical lens systems oriented towards the user's eyes (not shown) optionally having internal motors.

The illustrated example of the HMD device 344 is based, at least in part, on one or more straps 345 affixed to a housing of the HMD device 344 that extend, in whole or in part, around the user's head. supported on the head. Although not illustrated herein, the HMD device 344 may further have, for example, one or more external motors attached to one or more of the straps 345 , wherein automated corrective actions are performed on the user's head. using such motors to adjust such straps to modify alignment or other positioning of the HMD device.

that the HMD device may include other support structures not illustrated herein (eg, a nose piece, a chin strap, etc.) in addition to or instead of the illustrated straps. , and some embodiments may include motors attached to one or more such other support structures to similarly adjust their shape and/or locations to modify the alignment or other positioning of the HMD device on the user's head. It will be understood that there is Other display devices that are not attached to the user's head may similarly be attached to or be part of one or more structures that affect the positioning of the display device, and in at least some embodiments, one of the display devices motors or other mechanical actuators for similarly modifying their shape and/or locations to modify alignment or other positioning of the display device for one or more pupils of one or more users.

4 illustrates a simplified top plan view 400 of an HMD device 405 including a pair of near-to-eye display systems 402 and 404 . HMD device 405 may be, for example, the same or similar HMD devices illustrated in FIGS. 1-3 or a different HMD device, the HMD devices discussed herein being further used in examples discussed further below can The near-eye display systems 402 and 404 of FIG. 4 each have display panels 406 and 408 (eg, OLED micro-displays) and respective optical lens systems 410 each having one or more optical lenses. and 412). Display systems 402 and 404 include facing portion 416 (eg, the same as or similar to facing surface 343 of FIG. 3 ), left temple 418 , right temple 420 . , and an interior surface 421 that touches or proximates the face of the wearing user 424 when the HMD device is worn by the user. have. The two display systems 402 and 404 may be secured to a housing 414 in a spectacle arrangement that may be worn on the head 422 of a wearing user 424 , where the left temple 418 and the right temple 420 may be fixed. ) over the user's ears 426 and 428 respectively, while a nose assembly 492 can overlie the user's nose 430 . In the example of FIG. 4 , the HMD device 405 may be supported partially or entirely on the user's head by a nose display and/or right and left over-ear temples, while FIG. 2 and FIG. In some embodiments, such as the embodiments shown in 3, straps (not shown) or other structures may be used to secure the HMD device to the user's head. The housing 414 may be shaped and sized to position each of the two optical lens systems 410 and 412 in front of one of the user's ears 432 and 434, respectively, such that each pupil 494) is centered vertically and horizontally in front of the individual optical lens systems and/or display panels. Although housing 414 is shown in a simplified fashion similar to glasses for purposes of explanation, in reality more sophisticated structures (eg, goggles, integrated headband, helmet, straps, etc.) may be used to position and support display systems 402 and 404 on the head 422 of

The HMD device 405 of FIG. 4 , and other HMD devices discussed herein, provides virtual information to the user via a corresponding video represented at a display rate such as, for example, 30 or 60 or 90 frames (or images) per second. may present a reality display, while other embodiments of a similar system may present an augmented reality display to the user. Each of the displays 406 and 408 of FIG. 4 will produce light that is transmitted through and focused by respective optical lens systems 410 and 412 onto the eyes 432 and 434 of the user 424 , respectively. can The pupil aperture of each eye through which light is transmitted into the eye will typically have a pupil size ranging from 2 mm (millimeters) in very bright conditions to a whopping 8 mm in dark conditions. , whereas the larger iris comprising the pupil may have a size of approximately 12 mm - the pupil (and the surrounding iris) further typically the eye with the eyelids open by several millimeters in horizontal and/or vertical directions. can move within the visible portion of the , which will also move the pupil to different depths from the optical lens or other physical element of the display for different horizontal and vertical positions as the eye rotates around its center (which is the pupil resulting in a movable three-dimensional volume). Light entering the user's pupil is viewed by user 424 as images and/or video. In some implementations, the distance between the user's eyes 432 and 434 and each of the optical lens systems 410 and 412 can be relatively short (eg, less than 30 mm, less than 20 mm), and the optical lens system This can advantageously make the HMD device feel lighter to the user and also provide a larger field of view to the user as the weight of the arms and display systems is relatively close to the user's face. Although not illustrated herein, some embodiments of such an HMD device may include various additional internal and/or external sensors.

In the illustrated embodiment, the HMD device 405 of FIG. 4 is a hardware sensor, such as to include one or more accelerometers and/or gyroscopes 490 (eg, as part of one or more IMU units). and additional components. As discussed in more detail elsewhere herein, values from the accelerometer(s) and/or gyroscopes may be used to locally determine the orientation of the HMD device. In addition, the HMD device 405 may include one or more forward-facing cameras, such as camera(s) 485 on the exterior of the front portion 416 , the information of which may include, for example, an AR function or a positioning function. to provide, as part of the operations of the HMD device. Additionally, the HMD device 405 may be configured to control the display of images on other components 475 (eg, display panels 406 and 408 ), as discussed in more detail elsewhere herein. electronic circuits, internal storage, one or more batteries, a location tracking device for interacting with external base stations, etc.). Other embodiments may not include one or more of components 475 , 485 , and/or 490 . Although not illustrated herein, some embodiments of such an HMD device include various additional internal and/or external sensors for tracking various other types of movements and locations, such as the user's body, eyes, controllers, etc. can do.

In the illustrated embodiment, the HMD device 405 of FIG. 4 is configured to determine a user pupil or gaze direction, which may be provided and used in one or more components associated with the HMD device, as discussed elsewhere herein. It further includes hardware sensors and additional components that may be used by the disclosed embodiments as part of the described techniques for In this example the hardware sensors are near the optical lens systems 410 and 412 for use in obtaining information about the actual locations of the user's pupils 494, eg, separately for each pupil in this example. one or more eye tracking assemblies 472 of the eye tracking subsystem positioned on the inner surface 421 and/or mounted on or near the display panels 406 and 408 .

Each of the eye tracking assemblies 472 may include one or more light sources (eg, IR LEDs) and one or more light detectors (eg, silicon photodiodes). Additionally, although only a total of four eye tracking assemblies 472 are shown in FIG. 4 for clarity, it should be understood that in practice a different number of eye tracking assemblies may be provided. In some embodiments, four eye tracking assemblies are provided for each eye of user 424 , resulting in a total of eight eye tracking assemblies 472 . Further, in at least some implementations, each eye tracking assembly comprises a light source directed to one of the eyes 432 and 434 of the user 424, a light detector positioned to receive light reflected by the respective eye of the user; and a polarizer configured and positioned to prevent light reflected through specular reflection from being transmitted on the photo detector.

As discussed in greater detail elsewhere herein, information from the eye tracking assemblies 472 may be used to determine and track a user's gaze direction during use of the HMD device 405 . Further, in at least some embodiments, the HMD device 405 may, for example, correspond to one or both of the eye-proximity display systems 402 and 404 to correspond to actual locations of one or both of the pupils 494 . Alignment and/or other of one or more of the display panels 406 and 408 and/or optical lens systems 410 and 412 within the housing of the HMD device 405 to personalize or otherwise adjust everyone's target pupil location. One or more internal motors 438 (or other movement mechanisms) that may be used to move 439 positioning (eg, in vertical, horizontal left-and-right and/or horizontal forward-and-backward directions). ) may be included. These motors 438 may, for example, facilitate user manipulation of one or more controls 437 on housing 414 and/or user manipulation of one or more associated discrete I/O controllers (not shown). can be controlled through In other embodiments, HMD device 405 may include adjustable positioning mechanisms (eg, screws, sliders, ratchet) that are manually changed by a user, such as through use of controls 437 . ), etc.) can control the alignment and/or other positioning of the optical lens systems 410 and 412 and/or the display panels 406 and 408 without these motors 438 . . In addition, although motors 438 are illustrated in FIG. 4 for only one of the near-eye display systems, each of the near-eye display systems may have its own one or more motors in some embodiments, some In embodiments one or more motors may be used to control (eg, independently) each of multiple eye-proximity display systems.

While the techniques described in some embodiments may be used with a display system similar to that illustrated, in other embodiments, using a single optical lens and display device or using multiple such optical lenses and display devices. Other types of display systems may be used, including one. Other non-exclusive examples of such devices include cameras, telescopes, microscopes, binoculars, spotting scopes, surveying scopes, and the like. In addition, as discussed elsewhere herein, the described techniques can be combined with a wide variety of display panels or other display devices that emit light to form images that one or more users view through one or more optical lenses. can be used together. In other embodiments, a user may view one or more images generated otherwise than through a display panel, such as on a surface that partially or fully reflects light from another light source (eg, a laser scan beam). It can be seen through an optical lens.

Exemplary display systems

5 is a schematic block diagram of a display system 500 , according to one non-limiting illustrated implementation. Display system 500 may be a display system of a head-worn display system, such as the head-worn display systems discussed above, or any other type of display system (eg, a wearable or non-wearable display system). can be Display system 500 may include a scan beam display system or other type of display system (eg, micro-display). In at least some implementations, display system 500 may be one of two substantially identical display systems provided in a device, such as a head-worn display device.

The display system 500 includes a display light source 502 optically coupled to a pupil relay system 504 . The display light source 502 may include a laser scan beam light source, a micro-display, or any other suitable display light source. The pupil relay system 504 is positioned to relay a first pupil from the display light source 502 to a second pupil in the viewer's eye 506 (or other image plane, surface, or material). The pupil relay system 504 includes polarization sensitive optics 508 (eg, polarization sensitive optics 508 ) that may include one or more of a waveguide-based optical system, a pancake optical system, a birdbass optical system, a coating-based optical system, or other optics. for example, post-scan optics). Polarization sensitive optics 508 may include one or more components. The efficiency of polarization sensitive optics 508 may be very sensitive to the polarization of light passing therethrough. That is, different polarizations will significantly change the intensity and stray light coming from the polarization sensitive optic 508 .

To optimize the polarization of light provided to polarization-sensitive optics 508 , pupil relay system 504 of display system 500 provides uniformly polarized light to polarization-sensitive optics 508 , or more generally, and a spatially varying polarizer 510 having a spatially varying polarization as a function of position, which functions to compensate for changes in polarization to provide optimized polarized light. For example, polarization-sensitive optics 508 may be configured to compensate for or “undo” any of the polarizations that one or more mirrors or other optics generate from compound angles.

The spatially varying polarizer 510 may include a wave retarder formed of a birefringent material. Birefringence is a property of a material with an index of refraction that depends on the polarization and propagation direction of the light. The wavelength retarder changes the polarization state or phase of light traveling through the wavelength retarder. A wavelength retarder can have a slow axis (or extraordinary axis) and a fast axis (ordinary axis). As polarized light travels through the wavelength retarder, light along the fast axis travels faster than along the slow axis.

As discussed above, the spatially varying polarizer 510 allows for a more uniform and efficient distribution of light from the display light source 502 to the polarization-sensitive optics 508 in the field of view (eg, axial- It can provide a phase delay that varies as a function of position (eg, horizontal position, vertical position, radial position) across on-axis versus off-axis. The particular manner in which the delay of the spatially varying polarizer 510 varies is the optical system(s) of the display system 500, such as the polarization state of the incident light, angle(s) of incidence, materials, geometry of the various components, etc. may depend on the specific construction and materials of

As an example, the spatially varying polarizer 510 may not provide a delay at a first position, and a delay to provide a delay of λ/4 (or other value) at a second position of the spatially varying polarizer. can be increased linearly. In general, the spatially varying polarizer 510 can provide a delay that varies in any way as a function of position, and the amounts of delay can be any value (eg, λ/20, λ/10, λ /4, λ, 2λ). Additionally, the amount of delay may only increase in one or more directions, only decrease in one or more directions, or increase and decrease. The amount of delay may vary continuously, or may vary in multiple steps.

The amount of delay may vary according to any type of function, including, for example, linear functions, polynomial functions, exponential functions, step functions, other types of functions, or combinations thereof.

In at least some implementations, the spatially varying polarizer 510 is a waveplate-like retardation film that provides precise and customized levels of broadband, narrowband or multiband delay in a single thin film. It may be formed as a multi-twist retarder (MTR). More specifically, the MTR has a single alignment layer and includes two or more twisted liquid crystal (LC) layers on a single substrate. Subsequent LC layers are directly aligned by previous layers, which allows for simple fabrication, achieves automatic layer registration, and results in monolithic films with continuously changing optical axes.

6 is a schematic diagram of a scan beam display system or projector 600 , according to one non-limiting illustrated implementation. The scan beam display system 600 includes a light source 602 , which may be a laser light source that emits a beam 604 . Light source 602 may include two or more light sources, such as a red light source, a green light source, and a blue light source. In such cases, a plurality of light sources may be combined into a single beam by a beam combiner. In at least some implementations, light source 602 is one or more color light sources (eg, red, green, blue) and an infrared or ultraviolet beam that may be used for various purposes, such as eye tracking. It may include a light source emitting an invisible beam such as

Beam 604 is incident on a scanning platform 606 , which may include a microelectromechanical system (MEMS) based scanner, and a scan mirror 608 of the platform to produce a controlled output beam 610 . ) is reflected from The scanning platform 606 may include a diffractive optical grating, a moving optical grating, a light valve, a rotating mirror, a movable silicon device, a digital light projector device, a flying spot projector, a liquid crystal on silicon (LCoS) device, or other It may include scanning or modulation devices. The scanning platform 606 includes one or more drive circuits selectively controlled by a controller 612 coupled to the scanning platform and light source 602 , which may include any suitable control circuitry having one or more components. can be combined. The drive circuitry enables the scanning mirror 608 to cause the output beam 610 to produce a scan, such as a raster scan, to produce an image displayed on an image plane, such as a viewer's eye 614 or a display surface. Modulates the direction in which the incident beam 604 is deflected.

7 is a schematic diagram of a scan beam display system or projector 700 according to one non-limiting illustrated implementation. The scan beam display system 700 may be similar or identical to the scan beam display system 600 of FIG. 6 in many respects. As such, like elements are referenced by like numbers, and discussion of these elements is not repeated herein for the sake of brevity.

Scan beam display system 700 includes post-scan correction optics 702 (“post-scan optics”) and collimation optics 704 . Post-scan optics 702 may include one or more optics positioned in the optical path after scanning platform 606 , commonly referred to herein as “post-scan”. The post-scan correction optics 702 may be designed and configured to correct or adjust one or more distortion artifacts in the projected image. Examples of such distortion may include smile distortion, pin cushion distortion, barrel distortion, off-axis projection-based distortion, and the like. It should be understood that these are merely non-limiting exemplary types of which post-scan correction optics 702 may correct.

Post-scan optics 702 may include one or more of a waveguide-based optical system, a pancake optical system, a birdbath optical system, a coating-based optical system, and the like. Post-scan optics may include one or more components. The efficiency of the post-scan optics 702 can be very sensitive to the polarization of light passing therethrough. That is, different polarizations will significantly change the intensity and stray light coming from the post-scan optic 702 . In at least some implementations, display system 700 also includes collimating or beamforming optics 704 that can be used to at least partially recover the loss of infinity focus caused by post-scan optics 702 . ) may be included.

Display system 700 includes scan mirror 608 and post-scan optics 702 to provide polarization compensation for post-scan optics 702 , which may be very sensitive to polarization as discussed above. ) further comprising polarization compensating optics in the form of a spatially varying polarizer 706 positioned between The spatially varying polarizer 706 may be located, for example, on, adjacent to, or within the post-scan optics 702 . In other implementations, the spatially varying polarizer 706 may be positioned somewhere else in the light path between the light source 602 and the displayed image (eg, pre-scan, post-scan, adjacent to the light source, etc.) ) is located.

In at least some implementations, the controller 612 is operative to the spatially varying polarizer 706 to selectively vary the spatially-dependent phase retardation of the spatially varying polarizer to any desired configuration. can be combined. In such implementations, one or more additional thin film transistor layers may be provided that allow the spatially-dependent phase delay of the spatially varying polarizer 706 to be selectively controlled by the controller 612 . The controller 612 may control the phase delay at any desired rate, such as once, periodically, at a rate equal to or a fraction of the frame rate of the display system 700 , and the like. As an example, the spatially varying polarizer 706 may include a stack of multiple (eg, 2, 4, 10, 15) layers, each of which is in an active or inactive state. can be independently and selectively controlled. Thus, controller 612 may then selectively activate multiple layers, either in combination with one another, or one of the layers to provide the desired spatially-dependent phase delay.

8 is a display system 800 including a waveguide-based optical system and polarization compensating optics in the form of a spatially varying polarizer for use in a head-worn display system, according to one non-limiting illustrated implementation. ) is a schematic diagram of The display system 800 may include a lens or support structure 802 (eg, prescription or non-prescription spectacle lenses). The planar waveguide structure 804 may be at least partially embedded in the structure 802 or may be located proximate to the structure (eg, in front of or behind the structure). Waveguide 804 may be a rectangular (or other shaped) prismatic structure formed from a material having an index of refraction sufficiently different from that of a surrounding structure (e.g., structure 802) to provide total internal reflection within the waveguide. have.

To enable light to be coupled into the waveguide 804 , the display system 800 includes an in-coupler 806 physically coupled to a first portion of the waveguide.

Similarly, to enable light to be coupled out of the waveguide 804 towards the viewer's eye 810 , the display system 800 may include an out-coupler physically coupled to the second portion of the waveguide. ) (808). Display light that is in-coupled through the in-coupler 806 and out-coupled through the out-coupler 808 is, as discussed above, a display light source such as a projector, a scanning laser projector, a micro display, or from other display light sources. As non-limiting examples, couplers 806 and 808 may include one or more of diffraction gratings, holograms, holographic optical elements, volume diffraction gratings, surface relief diffraction gratings, etc. have.

Couplers 806 and 808 may also be reflective-type couplers or transmissive-type couplers. As an example, structure 802 may include a right eyeglass lens, and in-coupler 806 may be positioned near the edge of the eyeglasses proximate to a display source (eg, a projector) and out-coupler can be positioned towards the center of the spectacle lens so that the viewer can see the light from the waveguide 804 while looking straight ahead, or roughly straight ahead.

Display system 800 further includes polarization compensating optics in the form of spatially varying polarizer 812, various examples of which are shown in FIG. 8 as spatially varying polarizers 812a-812e. In the non-limiting illustrated example, illustrative examples 812a - 812e of a spatially varying polarizer 812 are shown located at several non-limiting illustrative locations of the display system 800 . In particular, 812a is adjacent to in-coupler 806 on the side towards the display source to provide polarization compensation for light entering waveguide 804, which may be very sensitive to polarization, as discussed above. to show the spatially varying polarizer positioned by The spatially varying polarizer 812b is shown in FIG. 8 as positioned adjacent the in-coupler 806 on its opposite side relative to the exemplary spatially varying polarizer 812a . Similarly, the spatially varying polarizer 812c is shown positioned adjacent the out-coupler 808 on the side facing the user's eye 810 , the spatially varying polarizer 812d being its opposite It is shown positioned adjacent to the out-coupler 808 on the side. The spatially varying polarizer 812e is shown positioned within the waveguide 804 at a location between the in-coupler 806 and the out-coupler 808 . It should be understood that the spatially varying polarizer 812 may be located, for example, on, adjacent to, proximate to, or within the waveguide 804 . In other implementations, the spatially varying polarizer 812 is positioned elsewhere in the optical path between the viewer's eye and the display light source to provide polarization compensation.

9 shows a side elevational view of the components of an HMD system 900 according to one non-limiting illustrated implementation. HMD system 900 includes a display panel 902 , such as an OLED, LCD, or other type of display panel, and an eye box in which a user's eyes can be positioned to view images from the display from the display. ) 906 , including an optical lens 904 that provides image information. Lens 904 may include a single lens or a plurality of lenses. The HMD system 900 may include two display panels and two lenses, one for each eye of the user. In operation, the light 910 emitted by the display panel 902 is optically modified (e.g., For example, it can be focused).

The polarization-based optical distortion phenomenon may be caused, in part, by different angles of arrival of different light rays when passing through a curved optical lens, such as lens 904 . Thus, for a set of pixels located along a central region of a display panel, light emitted from them can pass through the optical lens along its central axis with little or no bending of the different rays, which It can have some effect on polarization. Conversely, light rays located further from the central portion of the display panel 902 passing through the optical lens 904, which have a greater degree of curvature of the optical lens at these locations, will have their polarizations affected differently. can

To compensate for varying effects on the polarization of light emitted by display panel 902 , spatially varying polarization compensating optics 908 may be provided in at least some implementations. In the illustrated example, polarization compensating optics 908 may be positioned adjacent the front surface of display panel 902 and optionally applied to a suitable adhesive (eg, optically clear adhesive (OCA)). may be attached to or laminated to the display panel. Polarization compensating optics 908 may be formed of a phase retardation material (eg, a waveplate), such as a multi-twist retarder, as discussed elsewhere herein.

Polarization compensating optics 908 may provide spatially varying polarization defined by the phase map. 10 and 11 show two non-limiting examples of surface phase maps for polarization compensating optic 908 . In the example surface map 1000 of FIG. 10 , the phase is changed concentrically from the center of the optic toward the outer periphery between the -0.433 wavelength and +0.433 wavelength. In the example surface map 1100 of FIG. 11 , the phase varies linearly from -1.25E+004 at the bottom (as shown) of the optic 908 to +1.25E+004 at the top of the optic 908 , The units here are periods of 2π radians each. It should be noted that although the phase variation of the surface maps 1000 and 1100 is shown as discrete steps for simplicity, in practice the phase may vary continuously across the surface of the optic.

In at least some implementations, the surface phase map of the compensating optic 908 may be designed to cancel or compensate for undesirable polarization caused by at least one of the display panel 902 or the lens 904 . . In such implementations, a phase profile or map of an optical system (eg, a lens, or a lens and a display panel) may be determined first. The determined phase map may then be inverted and applied to compensating optics 908, which cancels undesirable effects caused by other components of the optical system.

In at least some implementations, polarization compensation optics 908 can improve the polarization performance of HMD system 900 for light at low angles of incidence.

In addition to or as an alternative to polarization compensation, the compensation optics 908 may be configured to shape the light from the display panel 902 to be more telecentric, so that the light is more uniform and telecentric. The lens 904 is reached with trickly aligned angles. This feature advantageously provides improved performance across the entire eye box 906 .

By using the spatially varying polarizers discussed herein, optical designers have much more freedom to produce optical systems with improved performance and efficiency, which provides a better viewing experience and at a lower cost. It enables display systems that are smaller in size or weight, consume less power, and provide other advantages that will be apparent to those skilled in the art.

The various implementations described above may be combined to provide additional implementations. These and other changes may be made to the implementations in light of the above detailed description. In general, in the following claims, the terminology used should not be construed to limit the claims to the specific implementations disclosed in the specification and claims, but rather all possible implementations along with the full scope of equivalents to such claims. It should be construed as including examples. Accordingly, the claims are not limited by this disclosure.

Claims (24)

A display system comprising:
display light source; and
a pupil relay system positioned to relay a first pupil from the display light source to a second pupil in a viewer's eye, the pupil relay system comprising:
polarization-sensitive optics; and
and a spatially varying polarizer having a spatially varying polarization as a function of position to provide polarization compensation for the polarization sensitive optics.
The method according to claim 1,
wherein the spatially varying polarizer comprises a multi-twist retarder.
The method according to claim 1,
wherein the spatially varying polarizer does not provide a delay in a first position and provides a quarter wavelength delay in a second position.
The method according to claim 1,
wherein the delay of the spatially varying polarizer varies as a function of either a horizontal dimension or a vertical dimension.
The method according to claim 1,
and the delay of the spatially varying polarizer varies across the field of view of the display system.
The method according to claim 1,
wherein the polarization-sensitive optics comprise a waveguide-based optical system, a pancake optical system, a birdbath optical system, or a coating-based optical system.
The method according to claim 1,
wherein the display light source comprises a laser light source, the display system further comprising a scan mirror positioned to receive a beam of light from the laser light source and relay the received light towards the pupil relay system.
8. The method of claim 7,
The display system further comprises a beam forming optic positioned between the laser light source and the scan mirror.
The method according to claim 1,
and at least a portion of the spatially varying polarizer is located on, adjacent to, or within the polarization-sensitive optic.
The method according to claim 1,
wherein the polarization-sensitive optics include a waveguide, and wherein the spatially varying polarizer is positioned on, within the waveguide, or proximate a port of the waveguide.
The method according to claim 1,
wherein the display system is a display system of a head-worn display system.
The method according to claim 1,
The display system further comprises control circuitry operatively coupled to the spatially varying polarizer, the control circuitry operative to selectively adjust a delay provided by the spatially varying polarizer. which is a display system.
The method according to claim 1,
wherein the display source comprises a micro-display and the spatially varying polarizer is positioned adjacent the micro-display.
14. The method of claim 13,
and the spatially varying polarizer is attached to the micro-display.
14. The method of claim 13,
wherein the spatially varying polarizer provides telecentricity to light emitted by the micro-display.
14. The method of claim 13,
wherein the spatially varying polarizer comprises a surface phase map that provides polarization compensation for at least one of the display source and the polarization sensitive optics.
A head-worn display system comprising:
support structure; and
a display system coupled to the support structure, the display system comprising:
display light source; and
a pupil relay system positioned to relay a first pupil from the display light source to a second pupil in a viewer's eye, the pupil relay system comprising:
polarization-sensitive optics; and
and a spatially varying polarizer having a spatially varying polarization as a function of position to provide polarization compensation for the polarization sensitive optics.
18. The method of claim 17,
wherein the spatially varying polarizer comprises a multi-twisted retarder.
18. The method of claim 17,
wherein the delay of the spatially varying polarizer varies as a function of a horizontal dimension, a vertical dimension, or a field of view of the display system.
18. The method of claim 17,
wherein the polarization-sensitive optics comprise a waveguide-based optical system, a pancake optical system, a birdbath optical system, or a coating-based optical system.
A head-worn display system comprising:
support structure; and
a display system coupled to the support structure, the display system comprising:
laser light source;
a scan mirror positioned to receive a light beam from the laser light source; and
a pupil relay system positioned to relay a first pupil received from the scan mirror to a second pupil in a viewer's eye, the pupil relay system comprising:
polarization-sensitive optics; and
and a spatially varying polarizer having a spatially varying polarization as a function of position to provide polarization compensation for the polarization sensitive optics.
22. The method of claim 21,
wherein the spatially varying polarizer comprises a multi-twisted retarder.
22. The method of claim 21,
wherein the delay of the spatially varying polarizer varies as a function of a horizontal dimension, a vertical dimension, or a field of view of the display system.
22. The method of claim 21,
wherein the polarization-sensitive optics comprise a waveguide-based optical system, a pancake optical system, a birdbath optical system, or a coating-based optical system.

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